1. Technology Field
The invention relates to a data writing mechanism, and particularly relates to a data writing method, a memory storage device, and a memory controlling circuit unit for a rewritable non-volatile memory module.
2. Description of Related Art
The market of digital cameras, mobile phones, and MP3 players has expanded rapidly in recent years, resulting in consumers' escalated demand for storage media. The characteristics of data non-volatility, low power consumption, compact size, and no mechanical structure make the rewritable non-volatile memory module (e.g. flash memory) ideal for being built in the portable multi-media devices as cited above.
Generally speaking, the rewritable non-volatile memory module is used in combination with a host system. A volatile memory may be further disposed in the host system for storing some data of the host system during operation. If the host system is powered down suddenly or enters a sleep mode, the data in the volatile memory needs to be written to the rewritable non-volatile memory module. In some situations, the data in the volatile memory is sequentially dumped to the rewritable non-volatile memory module and the host system has to complete all writing within a preset time. Therefore, the rewritable non-volatile memory module also needs to complete a large number of sequential writing operations within the preset time. In other words, the speed of sequential writing needs to be higher than a target value.
With different managements of the rewritable non-volatile memory module, there is a trade-off between sequential writing and non-sequential writing. In general, management of the rewritable non-volatile memory module based on logical programming units achieves higher speed in non-sequential writing. On the other hand, if the management is based on logical erasing units, higher sequential writing speed is achieved. In normal operations, the host system executes non-sequential writing more frequently than sequential writing. However, a large number of sequential writing operations may be required in the case of a sudden power down or sleep mode. In the case of managing the rewritable non-volatile memory module based on the logical programming units, if sequential writing is performed after performing non-sequential writing for a period of time, the speed of sequential writing may drop significantly due to garbage collection, thus causing that a large number of sequential writing operations cannot be completed within the preset time. Therefore, how to ensure that the sequential writing speed is higher than the target value in the above cases is a concern of persons skilled in the art.
Nothing herein should be construed as an admission of knowledge in the prior art of any portion of the present invention. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention, or that any reference forms a part of the common general knowledge in the art.